Cylinder lock construction

ABSTRACT

A cylinder type lock having shield means encircling the tumblers therein is disclosed. The shield means is provided as a split line structure like the lock tumblers but can have a lifting or displacement travel thereof for moving the split line thereof to the lock shear line which is different than that required for an associated tumbler. Employment of shield means in association with a tumbler makes the lock more difficult to pick.

United States Patent [191 Tria, Jr. et a1.

[ June 25, 1974 CYLINDER LOCK CONSTRUCTION [76] Inventors: Leonard F. Tria, Jr., 560 St. George Ave., North Babylon, N.Y. 11703; Edward A. Wiacek, 1268 Burton Ave., Elmont, N.Y. 11003 22 Filed: Mar. 7, 1973 21'' App]. NO.: 338,988

[52 use! 70/359, 70/364 A, 70/378 [51 Int.Cl E05b 15/14, EOSb 27/04 58 Field of Search 70/364 A, 359, 378, 419, 70/421,376

[56] References Cited UNITED STATES PATENTS 593,436 ll/l897 Rydberg 70/359 917,365 4/1909 Schoell 70/359 1,095,500 5/1914 Hansen 70/359 2,653,467 9/1953 Segal 70/359 Primary Examiner-Robert L. Wolfe Attorney, Agent, or Firm-Watson, Leavenworth, Kelton & Taggart 3 Claims, 9 Drawing Figures PAIENTEU JUNZS m4 sum 3 BF 3 I 1 CYLINDER LOCK CONSTRUCTION BACKGROUND OF THE INVENTION Cylinder type locks havebeen in use for many years. This type of lock generally includes housing structure fixed in a door or other closure structure and a cylinder plug rotatable in or relative to the housing along a shear line from a locked to an unlocked position, the latter cylinder plug movement being effected with a key in the customary manner and serving to actuate an unlocking mechanism, e. g., shifting of a bolt from locking to open position. To maintain the cylinder plug in locked position, the lock is provided with a plurality of pins or split tumblers which ride in companion passages formed in both the housing and cylinder plug. The tumblers normally are spring biased to maintain them in a position in the passages in which the .split line of each tumbler is remote from the shear line. In this manner solid tumbler structure bridges the shear line and prevents cylinder plug rotation. To move the cylinder plug to an unlocked position, it is necessary to move all tumblers in opposition to the spring biasing acting thereon to position the split line of each at the shear line. Such movement generally involves moving each tumbler a different distance than that required for the others and for which purpose the key is provided with a series of cuts of varying depths.

While cylinder type locks offer a certain measure of security they nevertheless can easily be picked by persons having the requisite skill and experience needed for that purpose. All that need be done to pick the cylinder lock is to insert a tension bar in the key slot for applying torque to the cylinder plug and then rotating it to a certain extent as is possible due to the clearance tolerances between the tumblers and passages present in such locks. A pick is used in conjunction with the foregoing manipulation of the plug to raise or move the respective tumblers to align the split line of each with the shear line and cock or hang up the driver pin part of the tumbler on the partly rotated cylinder plug. When all tumblers have been thus raised and cocked, the cylinder plug will rotate freely.

It is desirable therefore that cylinder lock construction be improved in a manner as makes it difficult if not almost impossible to pick the same.

SUMMARY OF THE PRESENT INVENTION In accordance with the present invention, a cylinder lock is modified to provide it with spring-biased shield means associated with one or more of the tumblers therein. The shield means are disposed in one or more of the tumbler passages of the lock and are provided in split form in the same manner as the tumbler, i.e., each is comprised of first and second shield components. The shield components are concentric with and are disposed in encircling disposition about the tumbler and require that in order to unlock the cylinder plug for rotation, such components be moved along with the tumbler to a position in which the split lines of the shield components locate at the cylinder plug shear line. Preferably, the distance the shield components are required to be moved to locate their split line at the shear line is different than that distance of movement required for locating the split line of an associated tumbler at the shear line. The shield components can act as guards for the tumblers rendering access to the tumblers with a pick difficult. Additionally, to pick the lock it would be necessary to also lift the shield components, and since the latter desirably has different magnitude of movement than the tumblers, it would of practical necessity be required that two picks be used and that the precise lifting of both tumbler and shield means be effected, which occurrence is highly unlikely. Thus the shield means make the lock very difficult if not virtually impossible to pick.

Desirably, the lock is provided with shield means in association with each of the tumblers therein. Thus, for example, if the lock is the type employing five, seven, or more tumblers, a corresponding number of shield means will be employed in the lock. Also within the contemplation of the invention is lock construction in which one or more but less than all tumblers are provided with shield means.

The two shield components advantageously are provided as tubular members, advantageously as hollow cylindrical. members, and they are disposed in the tumbler passages such that the close tolerances of fit between the tumblers, associated shields and passage render it very difficult if not impossible to pick the lock because if an unauthorized person should succeed in raising shield components to align their split line with the lock shear line, the rotative force or torque applied during the picking operation and used to hang the driver shield part on the slightly rotated cylinder plug will cause binding of the enclosed tumbler against the shield and will thereby preclude moving the same due to the friction produced by the tight binding of the tumbler against the shield components.

It will be apparent that the employment of shield means in association with each tumbler is highly advantageous to prevent picking of a lock. The shields, as mentioned above, can act as guards to prevent convenient quick access to the tumbler pins with a pick and additionally, the shield means itself must be picked in tandem with its associated tumbler, a not easily accomplished task where different split line movement distances are involved. The net effect is to render the lock virtually unpickable or pickable with such difficulty as to dissuade the unauthroized persons endeavor because of the time that would be involved in such quest.

The present invention is applicable to all cylinder type locks, e.g., the type in which the cylinder plug is rotatable within the lock housing in which case the tumbler passages, tumblers and shield means will be disposed generally radially of the fixed axis about which the cylinder plug is rotated when moving the latter from a locked to unlocked position. The invention also is applicable to cylinder type locks in which the cylinder plug is in contact with a face surface of the housing and rotates relative thereto along a shear line defined by said contact surface. In this lock form the tumbler pins, tumbler passages and shield components will be disposed along axes extending longitudinally, e. g., parallel to the axis of rotation of the cylinder plug. The latter type lock employs a tubular type key and the tumbler pins therein generally are arranged in circular disposition about the axis of rotation of the cylinder plug. The first-mentioned type of cylinder lock is the more widely used type and employs a flat key insertable in the keyway formed in the cylinder plug to raise the tumblers.

A further embodiment of the invention provides that the shield means components are modified by cutting the activator shield component along a bias to reduce the shield component structure present in the keyway when the cylinder plug is in locked position. For example, the activator shield component can be provided as a cylinder cut on a bias. The bias cut structure thus can be positioned behind the tumbler activator pin so as to not be visible in the keyway to the purpose of misleading the unauthorized person into thinking that only the tumbler need be raised. Since the activator shield component would act to prevent cylinder plug rotation regardless of tumbler movement it thus would be very difficult if not impossible to pick the lock.

A particular advantage of the present invention is that the modification to a cylinder type lock can be effected by the lock manufacturer without any extensive alteration to the lock manufacturing line, and with but small increase in the manufacturing cost of the lock.

The invention, accordingly, comprises the lock possessing the features, properties and the relation of elements which will be exemplified in the devices hereinafter described and the scope of the present invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects of the invention will be in part obvious from the above discussion and will in part appear from the following detailed description taken in conjunction with the accompanying drawings, wherein like reference numerals indicate like parts throughout and in which: 7

FIG. 1 is a longitudinal sectional view through a cylinder lock of the type in which the cylinder plug rotates on a fixed axis within the lock housing, the tumblers and associated shield components being disposed radially of said fixed axis and in the position they occupy when the cylinder plug is in locked position.

FIG. 2 is a transverse sectional view of the lock shown in FIG. 1 as taken along the lines II-II therein.

FIG. 3 is a longitudinal sectional view of the lock shown in FIG. 1 following insertion of a key in the lock keyway to raise the tumblers and shield means to the shear line to permit movement of the cylinder plug from locked to unlocked position.

FIG. 4 is a horizontal sectional view of a cylinder lock of the type in which the cylinder plug is disposed adjacent with and rotates against a face surface of the housing, with the tumbler mechanism and shield means being disposed parallel to the axis of rotation of the cylinder plug, the tumblers and shield means being shown in the position they occupy when the cylinder plug is in locked position.

FIG. 5 is a view similar to FIG. 4 after a tubular key has been inserted in the keyway to move the split lines of the tumblers and shield components to the shear line as a requisite to rotating the cylinder plug from locked to unlocked position.

FIG. 6 is a fragmentary perspective view depicting the manner in which the tubular key associated with the lock shown in FIGS. 4 and 5 is modified at the lock receivable end thereof to actuate the shield components concurrent with the movement of the tumblers to the lock shear line when the key has been inserted in the lock.

FIG. 7 is a fragmentary longitudinal sectional view of a cylinder lock of the type shown in FIG. 1 which has been modified to the extend of forming the activator shield component as a cylinder cut along a bias to reduce said shield component structure disposed in the keyway when the cylinder plug is in locked position and effectively hide or screen the same from view behind the tumbler activator pin, the tumbler and shield means being shown in the position they occupy when the cylinder plug is in locked position.

FIG. 8 is a sectional view as taken along the line VIII- -Vlll in FIG. 7.

FIG. 9 is a sectional view taken along the line IX-IX in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1-3, there is depicted a cylinder type lock 10 which includes a housing 12, a cylinder plug 14 received in and rotatable in the housing 12 and having connected therewith mechanism, for example, a bolt arm 16 for unlocking the lock when the cylinder plug 14 is moved from locked to unlocked position. The lock, as is conventional with such types, additionally includes a plurality of passages 18 formed in the housing and companion passages 20 formed in the cylinder plug, which passages align when the cylinder plug is in locked position. Also provided in the lock are a corresponding plurality of split type tumblers which are under spring-biased force within passages 18 and 20, which biasing is applied by means of springs 22, the tumblers each comprising a lower or activating pin 24 and an upper or drive pin 26, the two pins being in abutment as shown at the split 28. When the cylinder plug is in locked position, the spring means 22 bias the tumblers downwardly to a position in which the split line 28 is remote from the shear line 62 defined by interface between the periphery of the cylinder plug and the lock housing so that the activating pins, at their lower tip ends, are in stopped abutment with a stopping ledge 30 formed in the keyway 32.

In accordance with the present invention, the lock 10 is provided with shield means associated with at least some of the tumblers, each shield means being comprised of first and second shield components 40, 42, which, in like manner as the tumblers are of split construction in which the said first and second shield components are in abutment at a split line as at 44. The shield components are received in the tumbler passages in encircling position about the tumblers and are slidable in the tumbler passages independently of the movement of the tumblers. Additionally, each shield means has associated therewith its own biasing spring 46 which biases the shield components downwardly into the keyway 32 when the cylinder plug is in locked position, the tip end of shield component 40 also engaging in stopped abutment with the keyway as at 50. The shield components, 40, 42 are provided as tubular elements, preferably as hollow cylindrical elements, and the upper shield component 42 may be necked in as at 52 to provide a retaining member for reception of the compression spring 46 therein to insure noninterference of spring 46 with the operation of the compression spring 22 associated with the tumbler.

The shield means associated with each tumbler optionally but desirably can be designed such that the shield components must be moved upwardly from the position shown in FIG. 1 a different distance than the corresponding movement required of the tumbler when key 60 is inserted in the keyway 32 in order to bring the split line 44 of the shield components to the shear line 62 of the cylinder plug. Since the movement distance of the shield components is different than that of the tumbler associated therewith, when an unauthroized person seeks to pick the lock, they may succeed .in raising the shield split line to the lock shear line. However, if the tumbler is moved the same distance, it will not have its split line at the shear line and will present solid structure at the shear line. Moreover, if only the shield is moved in order to keep it in raised position while attempting to next raise the tumbler, torque must be applied to the cylinder plug, which torque causes the tumbler to bind against the inner surface of the shield component preventing any further movement of the tumbler so as to bring its split line to the shear line.

As can be noted in FIG. 3, the keycuts 68 in key 60 need not be altered when the lock is provided with the shield means since the same key cut that raises the tumbler can be used to lift the shield means the distance required to bring the split lines of both to the shear line. The lock 10, shown in FIGS. 1-3, is arranged such that the tumbler passages, the tumblers, the shield components and the two compression springs associated with the tumblers and shield components are disposed radially of the fixed axis about which the cylinder plug 14 rotates when it is moved from locked to unlocked position. FIGS. 4 and 5 on the other hand depict a different embodiment of cylinder lock in which the aforementioned components are disposed longitudinally, e.g., parallel to the axis about which the cylinder plug rotates, the cylinder plug in this form of lock 100 being arranged such that the cylinder plug 102 is in contact with the housing 104 at a face surface of the latter, the said face, surface defining the shear line 106 about which the cylinder plug is rotated, the housing 104 and cylinder plug 102 being received in a lock casing 105 with the housing being held to the latter to prevent rotation thereof by means of pin 107. Referring now in greater detail to FIGS. 4 and 5, the cylinder plug 102 is connected as at 110 to unlocing mechanism 112 so that when the cylinder plug is rotated the lock will be unlocked. The cylinder plug is provided with a plurality of tumbler passages 114 and the, housing 104 is provided with a corresponding plurality of companion tumbler passages 116, there being received in the respective passages tumblers of the split type, each having an activating pin 118 and a driver pin 120, the latter being necked down and elongated as at 122 for reception thereon of compression spring 124. Each tumbler has associated therewith shield means provided in the same manner as described earlier, and including a first shield component 130 and a second shield component 132 arranged in alignment therewith and being in abutment at a line defining the shield split line 134. Additionally, a compression spring 136 is provided with each shield means to bias the same in order to maintain the position thereof such that the split line 134 of the shield means is remote from the shear line 106 of the lock. To prevent axial displacement of both the shield components and the tumblers beyond the position shown in FIG. 4, an annular abutment flange 109 is provided in known manner in the casing 105, in this type of lock to stop movement of the shield components and tumblers.

With the tumblers and shield components positioned as shown at FIG. 4, the cylinder plug 102 cannot be rotated about shear line 106. However, when key 140 (FIG. 5) is inserted in the lock, abutment shoulders 142 and 144 thereon engage respectively the tip ends of the tumblers and first shield component 118 to displace them in a direction opposed to the bias of the cOmpression springs and move them so that their split lines are disposed at the shear line 106. The cylinder plug 102 thus can be rotated to unlocked positioning for opening the lock.

FIG. 6 shows the end face of the tubular key 140 and the manner of formation of abutment shoulders I42 and 144 thereon which engage with the tumbler and shield components, respectively.

FIGS. 7-9 show a further embodiment of lock construction 200 in which the shield means is formed so that it is virtually hidden from view when positioned in the lock keyway. This form of construction has the advantage that the would be lock picker, if he makes visual inspection of the keyway, may see the respective tumbler pins, but since the shield is hidden behind the tumbler pins he will be unaware that the lock is provided with shields. As seen in FIG. 7, the lock 200 includes a cylinder plug 214 rotatable in housing 216, a keyway 232, a tumbler driver pin 226, a tumbler activator pin 224, a first shield component 240 and a second shield component 242, the tumber and shield components having split lines 228 and 244, respectively, there also being provided springs 222 and 246 for the same purposes described previously in connection with the FIG. I lock construction. In accordance with this embodiment of the invention, the shield component 240, which is an elongated hollow cylindrical component, is formed with a bias cut as at 272 from a location adjacent its point of abutment with shield component 242 toward the tip end of the shield component 240. As a consequence, shield component 240 is provided with wall structure of tapering configuration as best seen in FIG. 8, such wall structure being of laterally diminishing dimension toward the tip end. In this manner the portion of the first shield component which extends into the keyway when the lock is in locked position and as shown in FIG. 8, effectively is hidden behind the tumbler activator pin 224 and cannot be seen by one intent upon picking the lock. The diminished size of the first shield component 240 at the tip end thereof does not alter the manner in which the proper key for the lock will function to lift the shield components for unlocking the lock.

It is advantageous that the first shield component 240 be fixed so that it does not rotate about its own axis when it is moved as, for example, by the insertion of a key into the keyway so that when the lock is subsequently relocked, the first shield component will locate in the same hidden position again. For that purpose cooperative means are provided in the form of a projection 274 on the first shield component which rides in a slot 276 formed in at least cylinder plug passage 220 to function to prevent rotation of the first shield component 240.

It will be seen from the foregoing description that the present invention provides a lock construction which is highly advantageous in that it makes it very difficult if not impossible to pick the lock. In effect, the presence of the shield means doubles the numbers of shear lines the person picking the lock must properly locate in order to rotate the cylinder plug while at the same time with close tolerances, the proper displacement of the shield means and cocking thereof at the shear line will so bond the associated tumbler that the latter cannot be moved. Further, in the type of lock wherein a flat key is used, a standard cut key intended to raise the tumblers is also adapted with modification to riase the larger diameter shield components since the tumblers will rest at a lower point in the cut than the shields.

As those skilled in the art will appreciate, the shields provided by the present invention protect the lock tumblers from being picked acting as guards to that end, and additionally, present such additional structure, having its own independent shear line positioning requirement, as prevents unauthorized opening of the lock by picking. If the shield should be raised successfully to its proper shear line positioning, that accomplishment will bind the associated tumbler to prevent it from being raised or moved to a proper shear line positioning.

While in the foregoing description advantageous forms of the invention have been set forth in terms of the distance of movement required for positioning the split line of a tumbler and its associated shield components at the lock shear line as being different at least as to some of the tumblers, it is possible to employ the shields of the present invention in a lock construction in which the shield means and the tumblers are intended to be moved the same distance to position the split lines thereof at the shear line. Such lock would be difficult to pick since even though the distance of movement of the shield means-and tumblers to position their split lines properly would be the same, a slight surface height variation at the tip end of the picking tool would result in raising the shield means a different distance than the tumbler.

What is claimed is:

1. In a cylinder lock comprising a housing,

a cylinder plug rotatable relative to said housing along a shear line from a locked to an unlocked position for actuating an unlocking mechanism, said lock further including a plurality of split type elongated tumblers received in a like plurality of companion passages in said housing and said cylinder plug, the passages in said housing and said cylinder plug aligning with each other when said cylinder plug is in locked position,

means normally biasing each of said tumblers to a position in its associated housing and cylinder plug passages wherein the split line thereof is remote from said shear line preventing rotation of said cylinder plug, and a keyway in said lock for receiving a key to move said tumblers in opposition to said biasing means to a position wherein the split line of each is disposed at said shear line whereby said cylinder plug can be rotated relative to said housing, elongated tubular shields associated with said tumblers, each of said shields including first and second shield components split in like manner as said tumblers and being received in the associated companion passages of said housing and cylinder plug in encircling disposition about said tumblers, and

means normally biasing said first and second shield components to a position in said associated companion passages wherein the split line thereof is remote from said shear line the tip end of each first shield component when said first sheild component, its companion second shield component and the associated tumbler are biased to a position in which the split line of each is remote from said shear line extending into said keyway, reception of a key in said keyway being operative to move said first and second shield components in opposition to said shield biasing means to a position wherein said shield split line is disposed at shear line, the improvement comprising said first shield element being formed with a bias cut therein extending away from the second shield component and providing said first shield component with wall structure of laterally diminishing dimension, said first shield component tapering to an extent in which a portion thereof at and adjacent said tip end of said first shield component is of narrower lateral expanse than said tumbler.

2. The lock of claim 1 further comprising means associated with said first shield component for preventing rotation of said first shield component about its own axis during biasing movement of said first and second shield components to a position in which the split line thereof is disposed at said shear line.

3. The lock of claim 2 in which the means for preventing rotation of said first shield component comprises a projection on said first shield component extending radially outwardly therefrom and received in a slot formed in at least the cylinder plug passage associated therewith. 

1. In a cylinder lock comprising a housing, a cylinder plug rotatable relative to said housing along a shear line from a locked to an unlocked position for actuating an unlocking mechanism, said lock further including a plurality of split type elongated tumblers received in a like plurality of companion passages in said housing and said cylinder plug, the passages in said housing and said cylinder plug aligning with each other when said cylinder plug is in locked position, means normally biasing each of said tumblers to a position in its associated housing and cyliNder plug passages wherein the split line thereof is remote from said shear line preventing rotation of said cylinder plug, and a keyway in said lock for receiving a key to move said tumblers in opposition to said biasing means to a position wherein the split line of each is disposed at said shear line whereby said cylinder plug can be rotated relative to said housing, elongated tubular shields associated with said tumblers, each of said shields including first and second shield components split in like manner as said tumblers and being received in the associated companion passages of said housing and cylinder plug in encircling disposition about said tumblers, and means normally biasing said first and second shield components to a position in said associated companion passages wherein the split line thereof is remote from said shear line the tip end of each first shield component when said first sheild component, its companion second shield component and the associated tumbler are biased to a position in which the split line of each is remote from said shear line extending into said keyway, reception of a key in said keyway being operative to move said first and second shield components in opposition to said shield biasing means to a position wherein said shield split line is disposed at shear line, the improvement comprising said first shield element being formed with a bias cut therein extending away from the second shield component and providing said first shield component with wall structure of laterally diminishing dimension, said first shield component tapering to an extent in which a portion thereof at and adjacent said tip end of said first shield component is of narrower lateral expanse than said tumbler.
 2. The lock of claim 1 further comprising means associated with said first shield component for preventing rotation of said first shield component about its own axis during biasing movement of said first and second shield components to a position in which the split line thereof is disposed at said shear line.
 3. The lock of claim 2 in which the means for preventing rotation of said first shield component comprises a projection on said first shield component extending radially outwardly therefrom and received in a slot formed in at least the cylinder plug passage associated therewith. 